Numerical and experimental investigations on flow regulation of fuel vapor core pump

摘要

Vapor core pump, unlike traditional centrifugal pumps with bypass throttling, exhibits the superiority in active fuel regulation. The vapor-liquid two-phase flow inside vapor core pump is an interesting process over its full regulation range, which influences performance of the pump. In this paper, an enclosed radial straight blade vapor core pump is selected as the object. Through vapor-liquid two-phase numerical simulation, the configuration of the vapor core in impeller zone and the regulation performance of the pump are obtained under several typical operating conditions. The main innovation in the simulation is that vapor volume fraction inside the pump as a means of actual vapor core description is obtained through numerical method with the Schnerr-Sauer cavitation model based. Vapor-phase volume fraction, velocity, head, and efficiency in relation to the opening or fuel rate are calculated and analyzed with inlet or outlet load changing. Performance testing on a vapor core pump prototype is carried out to verify the numerical results. Comparison between the experiment and the simulation shows the acceptable difference between them and the effectiveness of the numerical method. Study results indicate that a vapor core pump has a wide active regulation range of fuel delivery rate. For pure vapor core conditions, a considerable efficiency loss is unavoidable. Inlet throttling and hydraulic loss in its impeller play a significant role in deviated flow regulation characteristics. The opening size and the inlet or outlet load affect the pump delivery performance, which could be used to choose proper operation conditions or regulation range where neither much efficiency loss nor other performance degeneration on the pump occurs.